I've got a name for your feature:
Core AnimationAs a long time Windows developer I had my head burried in the sand about Macs. Since I've been learning it, it's been a revelation. If you have programmed on it you have no idea how nice it is to have a platform where all the cool stuff is in the native API. On Windows I have to make a really awkward decision: Use WPF to get the cool graphics, but then suffer massive memory consumption, have to pInvoke to do all the stuff that inexplicably hasn't been wrapped by the framework yet (anything to do with the shell, anything to do with media beyond a simple "play video" control); or you program native and have to invent everything from scratch.
On the Mac I'm missing managed code, but Objective-C isn't too bad. Hey, it's got databata binding in a native language without the ugly bandaid that is 'dependency properties' in WPF. And I get flashy graphics straight from the OS instead of resource hogging library ontop of it. If I want to write my own video editing app I can do everything I need using the Quicktime API. What do you on windows? Is DirectShow even still supported, or do you just bite to bullet and write your own video decoding libraries (or licence them from a third party at huge cost). Oh, and if you want to do anything sophisticated with video from within WPF, good luck.
I'm not going to predict anything stupid like Macs are going to take over - Window's position is almost complete unassailable - but what a mess the developer story is on it. I mean a seriously ugly mess. But hey, adding one more API can't hurt can it?...